Before I buy any books for 4.0, I would like to know if the physical books (PHB, DMG, MM) have been edited after WotC updated their online definitions. This has been bugging me for a while now. A friend of mine said he bought a book this year, but that some spell definitions and such were not updated to the definitions that were released some years ago.
The books are not updated; if you buy them, you are expected take care of the updates yourself, by perusing the official rule update PDFs.
The alternative used to be simple: buy a subscription to D&D Insider. However, with the fifth edition coming soon, who knows how long they will keep the 4e sites running...
Another partial no.
D&D in particular has had negative response from publishing updated books. This is already difficult between major revisions, but the update between 3.0 and 3.5 was poorly received.
This is one of the reasons they don't want to update the core books too often. They do seem to be coming out with various confusing boxed sets though, but as I won't give money to Hasbro I'm not up on the new stuff.
It does seem really really awful that people need to either have a computer of some sort (laptop, phone, etc) or to print off pages of PDFs. I too would prefer actual updated hardcover books rather than houserules-feeling binders of paper.